diff --git a/core/src/main/kotlin/org/pastalab/fray/core/RunContext.kt b/core/src/main/kotlin/org/pastalab/fray/core/RunContext.kt
index f7c1004..072d170 100644
--- a/core/src/main/kotlin/org/pastalab/fray/core/RunContext.kt
+++ b/core/src/main/kotlin/org/pastalab/fray/core/RunContext.kt
@@ -858,6 +858,15 @@ class RunContext(val config: Configuration) {
     syncManager.wait(latch)
   }
 
+  fun threadSleepOperation() {
+    val t = Thread.currentThread().threadId()
+    val context = registeredThreads[t]!!
+    context.checkInterrupt()
+    context.pendingOperation = ThreadSleepBlocking(context)
+    context.state = ThreadState.Paused
+    scheduleNextOperation(true)
+  }
+
   fun scheduleNextOperationAndCheckDeadlock(shouldBlockCurrentThread: Boolean) {
     try {
       scheduleNextOperation(shouldBlockCurrentThread)
diff --git a/core/src/main/kotlin/org/pastalab/fray/core/RuntimeDelegate.kt b/core/src/main/kotlin/org/pastalab/fray/core/RuntimeDelegate.kt
index 1311c34..4138614 100644
--- a/core/src/main/kotlin/org/pastalab/fray/core/RuntimeDelegate.kt
+++ b/core/src/main/kotlin/org/pastalab/fray/core/RuntimeDelegate.kt
@@ -846,16 +846,40 @@ class RuntimeDelegate(val context: RunContext) : org.pastalab.fray.runtime.Deleg
     return probe
   }
 
-  override fun onThreadSleepDuration(duration: Duration?) {
-    Thread.yield()
+  override fun onThreadSleepDuration(duration: Duration) {
+    if (checkEntered()) {
+      Thread.sleep(duration)
+      return
+    }
+    try {
+      context.threadSleepOperation()
+    } finally {
+      entered.set(false)
+    }
   }
 
   override fun onThreadSleepMillis(millis: Long) {
-    Thread.yield()
+    if (checkEntered()) {
+      Thread.sleep(millis)
+      return
+    }
+    try {
+      context.threadSleepOperation()
+    } finally {
+      entered.set(false)
+    }
   }
 
   override fun onThreadSleepMillisNanos(millis: Long, nanos: Int) {
-    Thread.yield()
+    if (checkEntered()) {
+      Thread.sleep(millis, nanos)
+      return
+    }
+    try {
+      context.threadSleepOperation()
+    } finally {
+      entered.set(false)
+    }
   }
 
   override fun onStampedLockReadLock(lock: StampedLock) {
diff --git a/core/src/main/kotlin/org/pastalab/fray/core/concurrency/operations/ThreadSleepBlocking.kt b/core/src/main/kotlin/org/pastalab/fray/core/concurrency/operations/ThreadSleepBlocking.kt
new file mode 100644
index 0000000..437a058
--- /dev/null
+++ b/core/src/main/kotlin/org/pastalab/fray/core/concurrency/operations/ThreadSleepBlocking.kt
@@ -0,0 +1,13 @@
+package org.pastalab.fray.core.concurrency.operations
+
+import org.pastalab.fray.core.ThreadContext
+import org.pastalab.fray.core.concurrency.primitives.InterruptionType
+import org.pastalab.fray.rmi.ThreadState
+
+class ThreadSleepBlocking(val context: ThreadContext) : TimedBlockingOperation(true) {
+  override fun unblockThread(tid: Long, type: InterruptionType): Any? {
+    context.pendingOperation = ThreadResumeOperation(type != InterruptionType.TIMEOUT)
+    context.state = ThreadState.Enabled
+    return null
+  }
+}